Process for alteration of fat content in meat

ABSTRACT

The present invention relates to a method for the removal, addition, or exchange of marbling fat within meat pieces, an apparatus for practicing the method, and the meat product produced by practicing the method using the apparatus. The method includes piercing raw meat with a piercing implement, withdrawing the implement from the meat and then removing adhered fat from the implement.

This application is a divisional of application Ser. No. 08/297,882,filed Aug. 30, 1994.

BACKGROUND OF THE INVENTION

The present invention relates to a method for the removal, addition, orexchange of marbling fat within meat pieces, an apparatus for practicingthe method, and the meat product produced by practicing the method usingthe apparatus. The present invention can remove fat from meat, add fatto meat, or exchange marbling fat for another type of fat, or anothermaterial entirely.

FIELD OF THE INVENTION

A fundamental dichotomy exists in American dietary consumption of meatproducts between "healthy eating", and "good eating." On one hand, theepidemiological data linking increased blood cholesterol levels and highdietary intake of saturated fats with increased risk of heart diseasehas led Americans to decrease their consumption of red meats, and meatproducts in general. This is due mostly to the fact that hard marblingfat, present in finer cuts of beef in particular, is very high incholesterol and saturated fats. As a result, per capita consumption ofred meat in the United States has dropped steadily since 1976. On theother hand, the general public continues to associate well marbled cutsof meat with good eating quality. The present invention is aimed atsolving this dilemma in which both meat vendors and meat consumers findthemselves. In effect, the present invention provides both "healthyeating," and "good eating," simultaneously.

It is now widely recognized that blood cholesterol levels can be a majorindicator in determining whether or not an individual will suffer fromheart disease. Individuals with higher blood cholesterol levelsgenerally have a greater risk of developing heart disease thanindividuals with lower levels of cholesterol. It is also believed thatan individual's blood cholesterol level is influenced by a number ofdiverse factors, some genetic in origin, others environmental in origin.It is known, however, with certainty, that one environmental factorwhich affects blood cholesterol level is diet.

The major environmental factor which contributes to a relatively highblood cholesterol level is a diet high in saturated fats. A saturatedfat (also called a "hard" fat) is a fat which generally has no double ortriple bonds (i.e. has no points of unsaturation). It is known thatanimal fats are generally high in saturated fat content. These hard,saturated fats include such fatty acids as lauric acid, myristic acid,palmitic acid and stearic acid. "Soft," or unsaturated fats have notbeen implicated in heart disease. Some, such as linoleic acid, linolenicacid, and eicosapentaenoic acid are either essential nutrients, or aremetabolic antagonists to the harmful saturated fats and sterols,including cholesterol. Other unsaturated fats, such as arachidonic andeicosatrienoic acids, are precursors of prostaglandins, which areimportant triggers of various human biological responses. With theexception of a trace of arachidonic acid, all of the beneficialunsaturated fatty acids listed above are almost entirely absent from thefat found within red meat. Therefore, a simple way to lower bloodcholesterol levels is to limit the intake of red meat, and hence theintake of harmful fatty acids and cholesterol.

The "hard" and "soft" designation for saturated and unsaturated fats,respectively is in reference to the melting points of the differenttypes of fat. Fats melt at sharply lower temperatures as the amount ofunsaturation within the fat molecule increases. As a thumbnail rule,then, the lower the melting point of a fat, the greater itsunsaturation, and therefore the lesser its health risks.

Unfortunately, many individuals are unwilling to modify their diets toreduce their intake of saturated fats. In order to significantly lowerblood cholesterol levels, it is necessary to reduce the dietary intakeof animal products, and red meat in particular, and to replace it withvegetable products or other meat products such as fish and poultry,which are lower in saturated fats.

Therefore, what is needed, and what the present invention addresses, isthe need for control of fat composition and quantity, not merely thetotal elimination of fats. As noted above, a certain amount of fatwithin meat is necessary to give the meat good organoleptic qualities.The present invention allows the substitution of harmful saturated fatswith beneficial (or at least less harmful) polyunsaturated fats. Thepresent invention also allows for the introduction of marbling soft fatinto lean pieces of meat. Also, if desired, the present invention canremove fat from a cut of meat, without putting anything in its stead.Equally important, the present invention can do all of the above withoutcomminuting the meat, and without changing the appearance or flavor ofthe meat.

In regard to the animals to be consumed themselves, altering the typeand distribution of fat within food animals via breeding and managementis a problem which continues to plague feed-lot managers and animalbreeders. While genetics does play some role in the fat content of foodanimals, in ruminants such as cattle, sheep and goats, it is themetabolism of the rumen organisms which ultimately controls metabolicintake. Because the rumen organisms are controlled by their own genes,their metabolic activity is genetically independent from that of theanimal,

It is true however, that the gross quantity of meat fat within an animalcan be controlled by animal management, such as grass feeding. However,feed-lot or open range grass feeding is a low productivity practice, andthe meat produced by such programs has not won high praise in theAmerican beef market. For the present, and the foreseeable future, thegrain-fed animal is the only source of tender, juicy, high value redmeats. Unfortunately, such grain-fed animals are also the main source ofmeat marbled with hard, saturated fat.

In addition to saturated and unsaturated fats, animal fat can also becharacterized by where it is found within the animal. In general, fat isfound in one of two types of deposits: depot fat or marbling fat. Depotfat accumulates in thick layers outside the muscles. Marbling fatcomprises thin streaks within the muscles themselves. Depot fat can betrimmed from the meat by hand, whereas marbling fat cannot.

Within the muscles, marbling fat is held as a single droplet inside alarge specialized cell. These fat cells aggregate as thin streaks alongsmall blood vessels within the muscle. Individual cells may be as largeas 0.1 mm. The average size of the fat cells increases with the totalfat content of the meat, and the size of the local fat accumulation.

These marbling fat cells are rather delicate, but in the raw stateremain intact and separated from one another by thin cell walls formedalmost entirely of proteins. However, the fat cells rupture when themeat is cooked. This empties the contents of the cell into thesurrounding meat. Because most of the compounds which give meat itscharacteristic flavor are fat-soluble, it is the contents of themarbling fat cells that imparts to the meat its characteristic aroma andflavor.

2. Description of the Prior Art

Numerous methods and machines have been devised to remove fat fromanimal carcasses immediately following slaughter, to tenderize toughcuts of meat, and to lower the fat and cholesterol content of finishedcuts of raw meat. For instance, U.S. Pat. No. 1,334,694, issued Mar. 23,1920, to Dufresne et al, describes an apparatus to cut external fat fromslaughtered animal parts. The animal parts are drawn through heatedrolls, and forced over large cutting blades which remove external fatfrom the pieces. The fat so removed is then recovered for furtherprocessing. U.S. Pat. No. 3,091,791, issued Jun. 4, 1953 to Czaper, Jr.discloses a meat scraper for removing bone dust and fat residue fromfrozen meat which has been cut with a power saw. The meat scraperincludes a resilient blade which will remove the offensive boneparticles and other contamination from the meat, without marring thesurface of the meat.

U.S. Pat. No. 3,916,777, issued Nov. 4, 1975, to Earl, describes a meattenderizing system in which a pistol-like device having a plurality ofneedles is used to inject an enzyme solution into whole, dead,meat-bearing carcasses. The enzyme solution, which prevents tougheningof the meat, is injected into the animal carcass immediately after theanimal is killed, while the temperature of the carcass is still withinbody temperature range. The apparatus used to inject the solutionconsists of a plurality of multiple-needle injectors, and associatedholding tank and pumping means, which are used to pump the enzymesolution into the slaughtered carcasses. The needles do not reciprocate,nor does the apparatus remove fat or any other substance from thecarcasses.

Chapman, U.S. Pat. No. 4,778,682 (issued Oct. 18, 1988) describes amethod of preparing a low-fat, low cholesterol raw meat product. Themethod has two steps: The first step is to expose a thin layer of meatto ultraviolet light. The second step is to comminute the meat in achilled bowl with the addition of cold water, acid, and salt and foodphosphates. A quantity of fat and cholesterol will separate from themeat emulsion and adhere to the surface of the chilled bowl. Thedrawback to this process is that it cannot be performed on whole roastsor cuts of meat, but can only be used to treat comminuted meats such asground beef.

Another method to lower the fat content of ground meats is disclosed inU.S. Pat. No. 5,082,678, issued Jan. 21, 1992 to Margolis. The Margolismethod consists essentially of heating a patty of ground meat to a giventemperature (45° C. for ground beef patties), and applying pressure tothe cooked patty to exude a quantity of fat from the patty. Thisreference contains no mention performing the method on a whole piece ofmeat, such as a roast. The Margolis patent also describes injecting aflavoring solution into meat patties after they are cooked, so as toreplace the nonfat moisture and flavors which are exuded from the meatpatty along with the fat.

Paulus, U.S. Pat. No. 5,250,006, issued Oct. 5, 1993, describes anapparatus for tenderizing whole cuts of meat. The apparatus includes astage on which the meat is placed, and an array of tenderizing kniveswhich can be embedded and removed from the meat. The spaced tenderizingknives can be easily removed from the apparatus to facilitate cleaningand to lessen the chance of accidental injury to the operator from thesharp blades. The blades are not hollow, nor are they temperaturecontrolled in any manner.

A Canadian Patent No. 685,130, issued Apr. 28, 1964 to Wittag, disclosesan apparatus to treat the surface of meats to facilitate the adhesion ofsmall pieces of meat to form larger pieces of meat. The apparatusstrikes the meat surface with a plurality of whip-like cords. Thisruptures the surface cells of the cut of meat, which releases liquidswhich increase adhesion of the meat pieces.

Japanese Patent J6-1158-763-A describes the removal of surface fatderived from blocks of beef or pork using sheets of material made of ahydrophobic and lipophilic material such as polypropylene. JapanesePatent JO-3164-130-A describes a meat tenderizer which has controllingmeans to ensure that the tenderizing blades of the tenderizer onlypierce the hardest portions of the cut of meat.

A 1962 article and accompanying advertisement from The NationalProvisioner (Mar. 3, 1962) describes an apparatus for injecting hot fator other liquids into whole cuts of meat to create artificial marbling.The apparatus includes a pumping unit and a four-prong injector forpumping liquids into meat. The article only describes injecting fat orother liquid into lean, well-muscled meat. There is no discussionregarding removing fat from cuts of whole meat.

None of the above references, taken alone or in any combination, is seenas teaching or suggesting the present invention.

SUMMARY OF THE INVENTION

The present invention provides a method and an apparatus for theremoval, addition, or exchange of marbling fat within whole pieces ofraw meat.

The subject method of fat removal from raw pieces of meat involvespiercing the meat with a cold metal surface, the metal surfacepreferably being a needle or a blade. For fat removal purposes, theneedle or blade can be solid or hollow. The relative motion of the metalsurface disrupts the cell walls of the fat cells within the piece ofmeat. Local friction caused by the passing metal surface momentarilymelts the fat released from the ruptured fat cells, and the liquid fatcoats the cold metal surface. The low temperature of the metal surfacecauses the fat to stiffen onto the metal. The needle or blade is thenwithdrawn from the meat with the stiffened fat adhered to the cold metalsurface thereof. The solidified fat is scraped off the metal surface,and the process repeated.

The fat momentarily melted by the passing metal surface adheres to themetal surface because the surface energy of the fat/metal interfacesystem is less than a fat/fat or fat/aqueous interfacial surface. Thedecrease in the energy of the interfacial system ensures that theliquefied meat fat spontaneously adheres to the cold metal surface whichpierces the meat.

In more detail, the surface tension of a liquid (amongst other factors)is often a large controlling factor in interfacial adhesivity. Thesurface tension of fats, in general, is very low. This low surfacetension is decreased even further when trace amounts of surface activesolutes (surfactants) are present in the fat. This is true of meat fatswhich contain free fatty acids and monoglycerides, which act assurfactants. Additionally, fat has a very low heat of fusion and heatcapacity compared to the water present in the surrounding muscle cells.Both the heat of fusion and the heat capacity decrease with increasingtemperature (i.e. the increased temperature caused by the friction ofthe passing metal surface). Therefore, the low heat of fusion and lowheat capacity of the fat compared to the water will cause the fat tomelt when the metal surface passes. Upon melting, the very low surfacetension of the fat compared to the free water in the surrounding musclewill cause the fat to spontaneously wet and adhere to the cool metalsurface, where it hardens, even though the fat is surrounded byrelatively cool meat. This is possible because the cellular nature ofthe meat itself effectively reduces its thermal conductivity withoutreducing its heat capacity. In other words, the frictional heat from thepassing metal surface quickly melts the fat due to the low heat offusion of the fat and the low thermal conductivity of the meat, whilethe surface tension of the fat causes it to wet and adhere to the coldmetal surface.

The identity of the metal which makes up the piercing means is generallynot important for an effective interface between the metal and the fatbecause any metal surface will be wetted by a fat when the fat wouldotherwise be surrounded by an aqueous solution (as in the watercontained in the muscle cells of the meat). The surface area of themetal surface, i.e. it's roughness, should, however, be as great aspossible consistent with the need to wipe the congealed fat off thesurface once it is removed from the meat. The metal should have as low aheat capacity, and as high a thermal conductivity as possible. Apreferred metal is hardened and annealed Permanickel. However, any metalhaving a low heat capacity and a high thermal conductivity compared towater or meat can be used.

The subject method of fat addition to raw meat according to the presentinvention involves the flow of liquid fat (or other liquid material)from a reservoir tank, through hollow metal piercing means, and into rawmeat via orifices in the metal piercing means. For fat additionpurposes, the metal piercing means are preferably hollow needles orblades. The liquid to be inserted into the meat is maintained at ahigher temperature than the meat itself. The motion of the metalsurfaces through the meat wipes the fat into the colder meat, where itcongeals. The fat streaks so made resemble the natural marbling found inmeat.

A relatively small pressure on the liquid fat (or other liquid) withinthe reservoir tank overcomes the resistance to fat flow within the lumenof the metal piercing means. This pressure, however, is not sufficientto cause the liquid to spurt from the orifices and into the meat. Inother words, the liquid being introduced into the meat is not "pumped"into the meat. When the fat reaches the orifice of the piercing means,it is wiped into the meat by the relative motion between the metalsurface and the meat.

In view of the above discussion, and the detailed description whichfollows, it is an object of the present invention to provide a methodand apparatus to convert fresh pieces of raw meat containing unwantedhard marbling fat into pieces of raw meat having much less hard marblingfat.

It is also an object of the present invention to add more marbling fatof a desired type into lean meat pieces containing too little fat.

Yet another object of the present invention is to provide a method andan apparatus to remove unwanted hard marbling fat from cuts of raw meat.

Another object of the present invention is to provide a method andapparatus for replacing hard marbling fats in raw meats with anothermaterial, preferably a soft polyunsaturated fat.

A further object of the present invention is to provide a raw meatproduct comprising whole pieces of raw meat whose natural content ofhard marbling fat has been significantly lowered and optionally replacedby a different type of fat or other material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation schematic view of the present fat alterationapparatus having a single needle for the removal or addition of marblingfat to meat.

FIG. 2 is a magnified schematic view of the needle 5 shown in FIG. 1,detailing the eye and lumen of the needle.

FIG. 3 is a front elevation schematic view of the present fat alterationapparatus including a plurality of needles for the removal or additionof marbling fat to meat.

FIG. 4 is a side elevation schematic of the present fat alterationapparatus having a plurality of blades, rather than needles, for theremoval or addition of marbling fat to meat.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is made herein to the attached drawings. The same referencenumerals are used throughout the various views to indicate identicalelements or features of the present invention.

FIG. 1 depicts an embodiment of the subject apparatus having a holdingtank 1, filled with liquid 3, and surrounded by temperature controlmeans 2. The temperature control means can be any type of conventionalthermostated temperature control means including convective, radiative,or inductive heating coils, sleeves, blankets, etc.; refrigerationcoils, etc.; or any combination thereof. Preferably the temperaturecontrol means includes both heating and cooling elements, and athermostat to maintain the content of the reservoir at a constanttemperature. Also, when the liquid 3 is not to be inserted into a meatworkpiece, the liquid 3 itself may act as a temperature control, as whenthe liquid is a mixture of ice and water.

A piercing means 5 in the form of a hollow needle is connected to thereservoir 1. The needle is also in good thermal contact with the tankand its contents. The connection to the tank itself is such that theneedle can rebound up into the tank without damage should the needlestrike a solid object such as a bone. A lumen 7 is defined by the needle5, and is connected to a conduit 6. The conduit 6 is connected to, andcapable of transporting liquid 3 from the reservoir 1, to the lumen 7.Valve means, not shown, allow the conduit 6 to be closed, prohibitingliquid flow from the reservoir to the lumen. An opening, or eye 8 islocated at the sharp end of needle 5, and in communication with lumen 7to allow liquid to flow out of the needle and into a raw meat workpiece.

Reciprocating structure 4 is provided to induce a reciprocatingtranslational motion to the needle 5. The stroke of the reciprocatingmotion is long enough to force the needle into a raw meat workpiece 17placed on stage 13, and withdraw the needle completely from the raw meatworkpiece. The reciprocating structure 4 can be an eccentric on arotating cam shaft, a hydraulic piston, an air-pressure activatedpiston, or any other conventional assembly for imparting reciprocalmotion to a shaft. It is preferred that the reciprocating structure 4provide a constant or as near as constant velocity of the needle 5through the meat 17. For this reason, the preferred reciprocatingstructure is a direct drive hydraulic piston.

The stage 13 on which the workpiece rests includes an opening or hole 14therethrough. The opening 14 is in registration with the needle 5 so asto allow the needle to pass through the opening as the needle goesthrough the stroke of its reciprocating motion. Directly below the stage13 is a lower die 15 including a hole 16 therethrough. The hole 16 is inregistration with the opening 14, which, as noted above, is inregistration with the needle 5. The hole 16 in lower die 15 is capableof scraping fat or other material from the surface of the needle 5.Therefore, the inside diameter of the hole 16 should be only slightlylarger than the outside diameter of the needle 5. The lower die 15 alsoserves as a lower fat tray to capture fat removed from the meat. Thelower die may optionally include channels (not shown) adjacent the hole16 to direct the collected fat to a holding tank (not shown).

Directly above the meat is an upper die 9, and a fat tray 11. Both theupper die and the fat tray having openings or holes therethrough, 10 and12, respectively. These openings are also in registration with theneedle 5. The hole 10 in upper die 9 is identical to hole 16 in lowerdie 15, and functions in the same manner to remove fat adhered to thesurface of the needle 5. The function of the fat tray 11 is to capturefat removed on the upstroke of the needle as it is removed from themeat, to keep the fat from falling back onto the meat. Fat remaining onthe needle after the upstroke may be further removed as the needlepasses through hole 10, in which case the upper die 9 will function tocollect fat in the same manner as the lower die 15. As mentioned abovefor the lower die 15, both the upper die 9 and the fat tray 11 may havechannels therein, not shown, to direct fat away from the meat workpieceand to collect it in a holding tank, not shown.

The stage, dies, and fat trays may be made of any suitably rigidmaterial such as sheet or cast metal or a plastic resin.

FIG. 2 depicts a magnified view of the needle 5 of FIG. 1, showing thedetail of the lumen 7 and the eyes 8. The needle may include two opposedeyes, as shown, or may include a plurality of eyes spaced along thelength of the needle, in any desired configuration. This allows forflexibility in working with a wide variety of meat pieces. For instance,if large, lean pieces of meat were to have marbling fat insertedtherein, a needle having many eyes spaced along the length of the needlewould make the fat insertion process faster and more efficient. Verythin or delicate meat pieces may only require a needle having a singleeye for fat delivery.

FIG. 3 depicts an embodiment of the present invention including aplurality of needles 5. This embodiment of the invention is identical tothe embodiment depicted in FIG. 1 with duplication of the meat-piercingmechanism. The reciprocating structure 4, of course, accommodates theadded piercing needles. While the reciprocating structure may beconfigured to insert all of the needles into the piece of meatsimultaneously, it is preferred that the reciprocating structurealternately insert groups of needles into the meat workpiece, as shown.This alternating reciprocating motion prevents the meat 17 from beinglifted off the stage 15 by the friction of the needles. Upper and lowerdies 9 and 15 include a plurality of openings or holes therethrough, 10and 16, respectively, in registration with the plurality of needles 5.The fat tray 11 likewise includes a plurality of openings or holestherethrough 12. These openings are also in registration with theneedles.

FIG. 4 depicts another embodiment of the present invention in which themeat piercing means are no longer needles, but blades 5. As with theneedles discussed above, the blades include lumens running therethrough7, and eyes 8. The blade can include as many or as few lumens and eyesas necessary to inject marbling fat into a meat workpiece in a timelyand efficient manner. Additionally, the eyes 8 may be located at anyposition along the length of the blade. In all other respects, theembodiment shown in FIG. 4 is identical to the embodiment depicted inFIG. 3.

In regard to the piercing means 5, be they needles or blades, they canbe made of any sufficiently rigid metal having good thermalconductivity. A preferred metal is Permanickel alloy. The surface of thepiercing means should be as rough as possible, consistent with the needfor the dies 9 and 15 to remove fat adhered to the piercing means. Theoverall configuration of the piercing means may be acicular, saggitate,lanciform, hastate, ensate, ensiform, spindle-shaped, star-shaped, orany suitable configuration for piercing a raw meat workpiece. The holes10 and 16 in dies 9 and 15 must, of course, be complementary to theconfiguration of the piercing means 5.

In operation, fat is removed from a piece of meat by first placing themeat on the stage 11. The reservoir 1 is then maintained at a constanttemperature below the temperature of the meat workpiece, and preferablyat or below 0° C. This can be done using temperature control means 2, orby placing ice water 3 inside the reservoir. The machine is thenactivated.

The reciprocating piercing means will be forced through the meat workpiece, and through dies 9 and 15. Fat which congeals on the coldpiercing means will be removed therefrom by the dies. The meat workpiececan be agitated during the process, or the process can be paused, themeat workpiece rotated or flipped, and the process resumed. The processcontinues until the desired amount of fat has been removed from meat.

To add fat, or any other liquid material to a meat workpiece, thereservoir 3 is filled with the liquid material to be injected. Thereservoir is then heated via temperature control means 2 to a desiredtemperature, a temperature preferably warmer than the piece of meat tobe treated. The meat work piece is then placed on the stage 11 and theapparatus activated. When the desired amount of liquid material has beenadded to the meat, the apparatus is deactivated, and the meat removed.

The meat treated by either of the above methods can be prepared in thesame fashion as untreated meat. The treated meat product in which liquidfat has been added appears as naturally marbled meat due to the streakynature in which the needles deposit the fat into the meat. Because thefat is not "pumped" into the meat, but is drawn out of the needles bythe relative motion between the meat workpiece and the needles, the fatintroduced into the meat accurately duplicates natural marbling. In allother respects, the finished product resembles untreated meat.

EXAMPLES

The following examples are for illustration purposes only, and are notto be construed as limiting the claimed invention in any manner.

Example 1

A piece of fresh, raw, marbled, USDA choice, chuck blade roast steerbeef, 20 mm thick, was treated at 20° C. in the apparatus depicted inFIG. 1. The needle used in the apparatus was 60 mm long, and 1.5 mm indiameter, and maintained at a temperature of 0° C. by ice water placedin the holding tank.

The stroke of the needle was set at 50 mm, with a stroke rate of 120strokes per minute. The stroke length caused the needle to ascendapproximately 25 mm above upper top surface of the meat, and to descendthrough the meat to a point approximately 5 mm below the lower surfaceof the meat. The maximum needle velocity was approximately 12 meters perminute. The meat was agitated slightly between needle strokes.

The needle removed 80 mg of fat per minute from the meat. The initialfat content of the meat was 30% by weight. After 1 minute of treatment,the fat content was lowered to 5% by weight. In terms of caloric contentdue to fat, a reduction of from 81% calories due to fat to 43% caloriesdue to fat was achieved.

In 1 minute, 82% of the fat within 4 needle diameters of the needle hadbeen removed. The agitation of the meat between strokes resulted inpenetrations approximately 6 mm apart, on center. This large degree offat removal is surprising because it shows that fat cells several layersaway from the needle are being ruptured by the needle's passage. Usingthese data, to achieve quick and efficient fat removal from large piecesof meat, the needles of the apparatus should be spaced 6 mm apart oncenters, in staggered rows.

The final appearance of the meat remained unchanged after the process,except for the disappearance of much of the marbling. The meat wasroasted in standard fashion. The texture and flavor of the roast wasjudged good, although noticeably leaner and tougher than an untreatedroasted control piece.

Example 2

A piece of fresh, raw, lean, USDA good, chuck arm steer beef, 20 mmthick, was treated at 20° C. in the device shown in FIG. 1. As inExample 1, the needle was 1.5 mm in diameter, and 60 mm long. The eye ofthe needle was 0.3 mm diameter, 3 mm from the needle point. The eye ofthe needle was in contact with the needle lumen, which was approximately0.5 mm in diameter, and extended 57 mm from the eye of the needle to theoil reservoir.

The oil reservoir was filled with corn oil, and maintained at a constanttemperature of 50° C.

The stroke of the needle was set at 50 mm, with a stroke rate of 120strokes per minute. The stroke length caused the needle to ascendapproximately 25 mm above upper top surface of the meat, and to descendthrough the meat to a point approximately 5 mm below the lower surfaceof the meat. The maximum needle velocity was approximately 12 meters perminute. The meat was agitated slightly between needle strokes.

The needle delivered approximately 0.01 grams of oil per minute into themeat. The initial fat content of the meat was 5% by weight. After oneminute, fat content within four needle diameters of the needle was 9%.

The raw appearance of the meat remained unchanged after the treatment,although it appeared more moist. The meat was then boiled. Its cookedappearance was identical to an untreated control piece from the same cutwhich had been boiled under identical conditions. Taste tests revealedthe treated meat to be more tender, juicy, and flavorful that theuntreated control meat.

It is to be understood that the present invention is not limited to theembodiments or examples described above, but encompasses any and allembodiments within the scope of the following claims.

I claim:
 1. A method of altering marbling fat content of raw meatcomprising the steps of:piercing a raw meat workpiece with at least oneimplement for piercing while said implement is at a temperature; colderthan the temperature of the raw meat; withdrawing the implement forpiercing from the raw meat whereby marbling fat contained in the meat isadhered to the implement for piercing; and the removing adhered adheredfat from a surface of the implement for piercing whereby the marblingfat content of the raw meat workpiece is lowered.
 2. The method ofaccording to claim 1, wherein said piercing step, said withdrawing step,and said removing step are repeated approximately 120 times per minute.3. The method according to claim 2 wherein the temperature of said atleast one implement for piercing is reduced to 4° C. or less.
 4. Themethod according to claim 1, wherein the implement for piercing has atleast one lumen therein and at least one open eye communicating thelumen to space outside the implement for piercing, and furthercomprising the additional steps of:supplying a liquid material to the atleast one lumen; maintaining the implement for piercing at a temperaturegreater than that of the raw meat workpiece: piercing the raw meat withsaid implement; and then inserting said liquid material into the rawmeat workpiece.
 5. The method according to claim 4, wherein theimplement for piercing the raw meat workpiece is maintained at aconstant temperature above 40° C.